1. Field of the Invention
The present invention relates to a turbo compressor, a turbo refrigerator, and a method of manufacturing a turbo compressor.
Priority is claimed on Japanese Patent Application No. 2010-066553, filed on Mar. 23, 2010, the content of which is incorporated herein by reference.
2. Description of Related Art
As a refrigerator that cools or freezes cooling objects such as water, a turbo refrigerator having a turbo compressor that compresses and discharges a refrigerant gas is known. In the turbo compressor included in the turbo refrigerator, an impeller that sends the refrigerant gas in a predetermined direction in order to compress the refrigerant gas is provided so as to be rotatable (For example, refer to Japanese Patent Application, First Publication No. 2009-185713). The impeller is fixed to one end portion of a rotation shaft by a predetermined fastening member (such as a nut).
When the fastening member is fastened to the one end portion of the rotation shaft, in order to prevent co-rotation of the rotation shaft due to the fastening operation, the rotation of the rotation shaft needs to be regulated. Therefore, the other end portion of the rotation shaft is provided with a regulating portion having the shape of the head portion of a hexagon bolt, which is used for regulating the rotation. During fastening of the fastening member, in a state where the regulating portion is held by a rotation regulating tool (such as a wrench) and thus regulates the rotation of the rotation shaft, the fastening member is fastened to the one end portion of the rotation shaft. However, since the regulating portion is provided to protrude from an end surface of the other end portion of the rotation shaft, there is a problem in that the overall length of the rotation shaft is increased. As the rotation shaft is lengthened, for example, there is a problem in that the size of the turbo compressor is increased, resulting in an increase in the weight of the turbo compressor.
In order to solve the above-mentioned problems, an object of the invention is to provide a turbo compressor, a turbo refrigerator, and a method of manufacturing a turbo compressor, capable of reducing the overall length of a rotation shaft while a regulating portion used for regulating the rotation of the rotation shaft is provided in the rotation shaft.